Ventilation fan



FIG. 1 is a bottom perspective view of a ventilation fan of the present invention;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a first side view thereof;

FIG. 5 is a second side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The dash-dash broken lines depict unclaimed environment; the dash-dot-dash lines depict boundaries of the claim; all broken lines are unclaimed. 

CLAIM We claim the ornamental design for a ventilation fan, as shown and described. 